This invention relates to improved mechanical systems for handling spinnaker poles as used on sailboats.
Numerous patents are directed to various devices for spinnaker poles and related equipment for handling spinnaker sails as used on sailboats, and recognize some of the same difficulties and problems inherent therein as addressed by the present invention.
More particularly, modern sailboats (at least those over some minimal length; smaller boats are generally less sophisticated), and which are intended for relatively high performance, especially for racing (similarly, xe2x80x9ccruisingxe2x80x9d sailboats are commonly less sophisticated), typically xe2x80x9cflyxe2x80x9d xe2x80x9cspinnakerxe2x80x9d sails when sailing xe2x80x9coff the windxe2x80x9d. That is, when sailing upwind, sailboats typically rely on the combination of a mainsail and one or more jib sails; see, e.g., Keenan U.S. Pat. No. 6,070,545 for discussion of some of the considerations relevant to sailboats when sailing upwind. By comparison, when sailing off the wind, the jib is commonly lowered, and a spinnaker is flown.
A spinnaker may be considered to be a three-sided sail having an upper corner, or xe2x80x9cheadxe2x80x9d, that is hoisted to, or nearly to, the top of the sailboat""s mast. All three of the spinnaker""s edges are free, creating significant problems of sail control. (By comparison, a mainsail usually has one edge fixed to the mast and a second edge fixed to or closely constrained by a rigid spar, the xe2x80x9cboomxe2x80x9d, while a jib normally has its leading edge constrained by the headstay of the boat, but two free edges.) As usually employed, one of the two lower corners of the spinnaker is termed the xe2x80x9ctackxe2x80x9d, and the other the xe2x80x9cclewxe2x80x9d. As will appear below, the assignment of these terms to the corners of the spinnaker can vary depending on the orientation of the boat with respect to the wind, complicating the precise definition of terms.
Traditionally, that is, over approximately the span of the last century, one of the corners of a spinnaker has been controlled by attachment (typically by way of an intermediary fitting, or a short length of wire rope, or line) to an outboard end of a spinnaker pole. (There are also spinnakers designed to be flown without poles. The invention is not directly relevant to these.) An inboard end of the pole is usually releasably fixed to the mast of the boat at a pivot point; the pivot point is defined by a fitting attached to the mast. Commonly, the mast fitting is mounted on a car, which can be moved by control lines up and down along a track affixed to the forward side of the mast. The car position is thus varied to control the shape of the sail, and the car is also moved up and down to perform a xe2x80x9cdip-pole jibexe2x80x9d, as discussed in detail below. The outboard end of the pole is controlled by a number of lines. Typically these control lines include a topping lift, running upwardly to or near the masthead to hoist the outboard end of the pole, a foreguy or downhaul extending down toward the foredeck to prevent upward movement of the pole end, and a pair of guys extending aft on either side of the boat to adjust the attitude of the pole with respect to the longitudinal centerline of the boat.
The corner of the spinnaker adjacent to the outboard end of the pole at any time is termed the tack; the third corner of the spinnaker is termed the clew, and is controlled by a line led aft toward the stern of the boat, termed the sheet. The situation is further complicated (both as to precise definition of terms, and as to smooth sail-handling) by the fact that the attitude of the spinnaker and its connection to the boat by the pole and the various lines mentioned must be altered during sailing, as the boat""s attitude with respect to the wind changes.
More specifically, FIG. 1 shows a sailboat 10 on xe2x80x9cport tackxe2x80x9d, that is, with the wind W blowing over the left or xe2x80x9cportxe2x80x9d side of the boat. As shown, mast 12 supports a mainsail 14 and a spinnaker 16, the head 18 of which has been hoisted to the masthead 20. The tack 22 of the spinnaker 16 is releasably fixed to the outboard end 29 of a spinnaker pole 26, the inboard end 27 of which is pivotally attached to mast 12. As noted above, and as shown in further detail below, the inboard end of pole 26 is affixed to mast 12 at a fitting allowing the pole to pivot freely with respect to mast 12, and which can be moved controllably upwardly and downwardly along a track 42 affixed to the forward side of mast 12. A topping lift 25 supports the outboard end of pole 26; the topping lift typically runs down inside mast 12 to a cleat or other fixing device. A foreguy 32 prevents the pole tip from unrestrained upward motion. Tension in a guy 36 and in the spinnaker itself adjust the angular position of the pole with respect to the centerline of the boat. A sheet 28 controls the clew of the spinnaker. A headstay 30 and a backstay 40 brace mast 12 fore and aft; shrouds on either side (not shown) provide lateral support for the mast.
The manuever undertaken when it is desired to change the attitude of the boat with respect to the wind so that the wind W comes over the right rear, or xe2x80x9cstarboard quarterxe2x80x9d, of the boat is called a xe2x80x9cjibexe2x80x9d (sometimes xe2x80x9cgybexe2x80x9d); jibing the boat from its attitude in FIG. 1 therefore involves turning it rightwardly through 45xc2x0 or more. As part of this manuever, the spinnaker and pole must be controlled to assume the corresponding positions on the new starboard tack. In the spinnaker jibing procedure most pertinent to the present invention, the outboard end 29 of pole 26 is detached from the present tack 22, the pole is swung across the bow of the boat so that its end is disposed over the starboard side of the bow, and the outboard pole end 29 is attached to the present clew 24, which becomes the new tack. (In a so-called end-for-end jibe, practiced mostly with respect to smaller boats, the inboard end of the pole is detached from the mast and affixed to the new tack; the original outboard end of the pole is then detached from the former tack and affixed to the mast).
In simpler rigging schemes, mainly applicable to smaller boats, the line which forms the present guy 36 then becomes the sheet, while the present sheet 28 becomes the new guy. In the rigging arrangement commonly used on larger boats, pairs of both sheets and guys are provided, so that the lines used and their fittings can be optimized for the loads encountered. The extra sheet and guy are not shown in FIG. 1, to avoid complication. In the usual terminology, the xe2x80x9clazyxe2x80x9d sheet becomes the xe2x80x9cworkingxe2x80x9d sheet upon jibing; the guys similarly change status and name upon jibing.
A number of US patents which provide background for the present invention are directed to devices for simplifying the process of disconnecting the end of the pole from one corner of the spinnaker, reconnecting it to the opposite end, and for interchange of the lazy and working sheets and guys. See generally McAlpine U.S. Pat. No. 5,347,945, Nilsen U.S. Pat. No. 3,185,121, Aronowitsch U.S. Pat. No. 4,473,021, Wasowski U.S. Pat. No. 5,333,566, Klein U.S. Pat. No. 5,558,035, Tiesler U.S. Pat. No. 6,085,679, Hall U.S. Pat. No. 5,109,786, Moseley U.S. Pat. No. 3,207,114, and Ridder U.S. Pat. No. 3,228,372. Smith U.S. Pat. No. 4,164,193, Eglais U.S. Pat No. 4,598,658, Lillehook U.S. Pat. No. 4,773,345, and Murnikov U.S. Pat. No. 5,937,779 are also generally relevant to the various problems encountered in control of spinnakers and other sails on sailboats.
As noted, most of the cited art is directed to the problem of interchanging the sheets and guys, and disconnecting the pole end from one corner of the sail and connecting it to the other corner. A concern which is less often addressed but also very significant is the control of the pole itself. Although spinnaker poles have grown increasingly lightweight in recent years, thanks to the availability of sophisticated materials such as epoxy-impregated carbon and xe2x80x9cKevlarxe2x80x9d fibers, they are still large and unwieldy, and can be dangerous to handle, especially given the often-difficult conditions on the foredecks of ocean-going sailboats.
There are several different ways to exchange the corner of the spinnaker that is affixed to the outboard pole end during a jibe. As noted, smaller boats typically use the xe2x80x9cend-for-endxe2x80x9d jibe. In this manuever, the inboard end of the pole is detached from the mast fitting; the pole, with its weight borne by the topping lift (which on smaller boats is commonly connected to a xe2x80x9cbridlexe2x80x9d of wire rope extending between the pole ends; the downhaul or foreguy may be attached to a similar bridle on the opposite side of the pole), is swung through the xe2x80x9cforetrianglexe2x80x9d between the headstay and mast, and its previous inboard end is engaged with the corner of the sail that is then controlled by the sheet, i.e., the previous clew; the outboard end of the pole is then detached from the previous tack, and brought toward and engaged with the mast fitting, becoming the new inboard end. This process requires a crewmember to physically control the pole during the period it is free from the mast; this requires considerable strength and coordination with the other crewmembers, and is unsuitable for large boats.
On larger boats, therefore, the inboard end of the pole remains attached to the mast, while the outboard end is freed from the tack and pivoted over the bow as the boat turns through the wind. The sheet/guy arrangements shown in the patents referred to above, and others described therein and elsewhere, are commonly used to bring the outboard end of the pole into engagement with the new tack. See Ross, Sail Power, FIG. 147(a) -(c) for a further description of some of these arrangements.
In order that the spinnaker pole can swing from one side of the boat to the other during a jibe, its outboard end must pass by the forestay. Commonly, the pole is longer than the horizontal distance between the mast and headstay at its typical working height. The common practice employed to work around this problem is the xe2x80x9cdip-polexe2x80x9d jibe. As noted above, the fitting attaching the inboard end 27 of the pole to the mast 12 is commonly mounted on a xe2x80x9ccarxe2x80x9d sliding along a track 42 fixed to the forward side of the mast, under the control of opposed lines. In the dip-pole jibing manuever, the car is lifted while the topping lift is eased, lowering the outboard end of the pole toward the deck, so that the outboard end of the pole can be swung across the bow, passing between the headstay and deck.
The xe2x80x9cdip-polexe2x80x9d jibe manuever is sometimes known as a Vim jibe, after the 1958 12-meter yacht on which this practice was originated. See the Ridder patent at col. 3, and Ross. As noted by Ridder in particular, this manuever requires several well-trained crewmembers, since the lines raising the car and easing the topping lift must be operated by two crewmembers in synchronism to dip the pole, while others must operate the sheets and guys to swing the pole end beneath the headstay. The dip-pole jibing process is fraught with potential problems and even if successfully accomplished takes some time to perform properly, since all of the lines that are operated in performance of the maneuver must then be cooperatively adjusted in order to bring the sail to its proper shape and attitude. Specifically, saving of even a few seconds on each jibe is a potential advantage well worth pursuing, especially given the highly competitive nature of modern sailboat racing. Likewise, any improvement in the process that makes it more reliable or allows reduction in the number of crewmembers involved is highly desirable, from the point of view of speed and efficiency as well as that of safety.
The present invention is therefore directed to improvements in spinnaker pole control as employed in particular in dip-pole jibing manuevers, although the improved spinnaker handling gear provided according to the invention is useful in connection with other types of spinnaker control procedures, and with spinnaker poles that do not require the dip-pole manuever for jibing.
Another object of the invention is to provide improved equipment for securing a line at a predetermined position, such that the line can be brought to the desired position rapidly and reliably, secured instantly in a manner which eliminates frictional damage to the line, and released immediately when desired.
According to the present invention, a novel spinnaker pole control system, comprising both novel gear and a novel rigging arrangement, is provided. As above, the conventional pole car comprises a fitting for pivoting attachment of the inboard end of the spinnaker pole, and typically slides up and down along a track affixed to the forward side of the mast under the control of hoisting and lowering lines. According to one aspect of the invention, the conventional car is replaced with a new car to which the inboard end of the pole is secured. The car has the capability to automatically grip a xe2x80x9cpole control linexe2x80x9d at a predetermined position along the line; in the preferred embodiment, this predetermined position is defined by a xe2x80x9cslugxe2x80x9d fitting attached to the pole control line. According to the improved rigging arrangement of the invention, a single pole control line provides the functions previously performed by both the topping lift, that is, hoisting the outboard end of the pole, and by the car hoisting and lowering line, that is, control of the height of the car and thus of the inboard end of the pole; accordingly, adjustment of the pole control line allows the pole to be set at any desired height above the deck, which is important in controlling the spinnaker""s shape to maximize its efficiency in propelling the boat.
More specifically, according to the invention, a single pole control line runs from the outboard end of the spinnaker pole (or bridle, if used) upward to the masthead, downward to a sheave at the foot of the mast, upward to or through the car to a sheave at the upper end of the track (with a multipurchase tackle optionally interposed at this point), and downwardly to the mast base; at that point the pole control line can be led back to the cockpit and cleated off. The slug mentioned above is interposed at a desired position in the portion of the pole control line running upward from the sheave at the mast base to the car, and does not interfere with the passage of the line over the various sheaves. The slug and car cooperate to limit the extent the line runs upwardly through the car; that is, the line runs freely through the car until the slug reaches the car, at which point the slug is secured to the car, preventing further movement of the line through the car.
More specifically, when the pole is not in use, the pole control line must be free to allow the pole to be lowered to the deck, out of the way. When the pole is to be used, the line is pulled through the system until the slug encounters the car and is secured to the car. As noted, when the slug is locked to the car, the line cannot slide further through the car. Therefore, further movement of the line hoists the car (and thus the inboard end of the pole) and the outboard end of the pole by substantially equal increments. By properly locating the slug along the line at installation of the system according to the invention, the pole can thus be arranged to repeatedly take any desired attitude with respect to the mast; normally the slug will be located so that the pole is substantially perpendicular to the mast. As noted, further movement of the line will lift the pole without significantly changing its attitude with respect to the mast. In these aspects, the invention is useful with boats using all sorts of spinnaker poles, that is, those which practice the end-for-end jibe as well as those performing the dip-pole jibe.
As noted, a multipurchase tackle, typically providing a 3:1 ratio, can be interposed in the line between the car and the sheave above the car on the mast. The tackle simply comprises a sheave on the car and a second sheave on the mast above the car. This tackle reduces the load encountered in lifting the pole, and provides further advantages when employed in connection with the dip-pole jibe. Specifically, when it is desired to jibe the boat, the slug is released from the car, but the cockpit end of the pole control line is not released. Pulling the pole control line downwardly through the car therefore lifts the car and the inboard end of the pole, while simultaneously lowering the outboard end of the pole, xe2x80x9cdippingxe2x80x9d the pole and allowing its outboard end to pass between the forestay and deck. The tackle sets the ratio by which the inboard end is lifted with respect to that at which the outboard end is lowered when dipping the pole to jibe. After the pole is clear of the forestay, the line is pulled back upwardly until the slug is again engaged by the car; this automatically returns both inboard and outboard ends of the pole to their former locations, avoiding the xe2x80x9ctweakingxe2x80x9d of lines that is an inevitable part of the conventional practice. Further adjustments that may be desired in the pole height can then be made by adjustment of the free end of the pole control line, e.g., from the cockpit.
In a particularly preferred embodiment, the car and slug cooperate so that the slug can be released from the car in preparation for a jibe simply by pulling the line in a specific direction. Further, the car may be provided with a catch cooperating with a control arm fixed with respect to the mast, so that the slug is automatically released from the car when the car is lowered to its inactive position along the deck, simplifying the process of stowing the spinnaker and its gear when a new point of sail is anticipated. The same control arm may retain the car until needed, simplifying its preparation for the next use.
A novel design for the slug and the securing mechanism is also provided, which may find use elsewhere on sailboats in situations where lines are repeatedly secured at the same position.